How to create string of foreach results

I have an if statement inside a foreach inside a foreach. Result is this a list of numbers one in a line. Example:

I'd like to have this as a result in a variable instead:

"watchers": ["3", "2824", "28", "6374", "3887", "198", "1953", "3827"],

I currently have no real idea how to convert the foreach results to the example string. Powershell preferred but I have access to pretty much any language.

Edit: Rephrasing my question, and/or to be more specific, I have this CSV

user_id,ticket_id
253,24704
1257,24201
1257,17038
1257,22560
1257,22547
1925,24783
2452,24766
2452,24787
2453,24766
2453,24787

I'm trying to write a script that creates this JSON for me:

[{
“ticket_id”: “253”,
“watchers”: [“24704”]
}, {
“ticket_id”: “1257”,
“watchers”: [“24201”, “17038”,“22560”,“22547”]
}, {
“ticket_id”: “1925”,
“watchers”: [“24783”]
}, {
“ticket_id”: “2452”,
“watchers”: [“24766”,“24787”]
}, {
“ticket_id”: “2453”,
“watchers”: [“24766”,“24787”]
}
]

Solution

What you seem to be after is a Json string with a property called watchers whose value is an array of numbers, in which case constructing it manually is just wrong, you can use ConvertTo-Json, example:

$someNumbers = 0..10
$filteredNumbers = foreach ($number in $someNumbers) {
    if ($number -gt 5) {
        $number.ToString()
    }
}
ConvertTo-Json @{ watchers = $filteredNumbers } -Compress

# Outputs: {"watchers":["6","7","8","9","10"]}

If you wanted something exactly like the output you have in question and want to construct the string manually, you can first join the array of numbers with a delimiter ", " and then interpolate that string in a new string:

$numbersString = $filteredNumbers -join '", "'
'"watchers": ["{0}"],' -f $numbersString

# Outputs: "watchers": ["6", "7", "8", "9", "10"],

Based on comments and looking at the last edit on your question, assuming the CSV is in a file, you can use Group-Object on user_id:

Import-Csv path\to\thefile.csv |
    Group-Object user_id |
    ForEach-Object {
        [pscustomobject]@{
            ticket_id = $_.Name
            watchers = @($_.Group.ticket_id)
        }
    } | ConvertTo-Json

The output from the above using the sample CSV would be:

[
  {
    "ticket_id": "1257",
    "watchers": [
      "24201",
      "17038",
      "22560",
      "22547"
    ]
  },
  {
    "ticket_id": "1925",
    "watchers": [
      "24783"
    ]
  },
  {
    "ticket_id": "2452",
    "watchers": [
      "24766",
      "24787"
    ]
  },
  {
    "ticket_id": "2453",
    "watchers": [
      "24766",
      "24787"
    ]
  },
  {
    "ticket_id": "253",
    "watchers": [
      "24704"
    ]
  }
]